1. Technical Field
This invention relates to an electronic deice that includes speech recognition means for controlling the operation of the device in response to a spoken command.
Additionally this invention relates to a method of controlling a voice controlled operation, that includes the step of controlling an operation of an electrical device in response to a spoken command.
2. History of Related Art
The development and widespread use of mobile telephones in combination with the development within the field of speech recognition techniques have provided mobile telephones with numerous voice controlled functions.
Widespread use of mobile telephones in different environments, e.g. in cars, in streets with noisy traffic, etc. has driven the development of speech recognition techniques towards very noise tolerant speech recognition techniques capable of recognising commands in the form of e.g. words or numbers, despite the fact that the commands are pronounced by humans having different voices and using different inflections.
U.S. Pat. No. 4,644,107 discloses a voice-controlled telephone providing voice controlled dialing. A number to be dialed can be spoken digit-by-digit and dialed, automatically, or a name can be spoken and the telephone will automatically dial the number stored in a user""s repertory corresponding to the spoken name.
U.S. Pat. No. 5,007,081 discloses a speech activated telephone. The speech activated telephone stores a plurality of spoken words, the telephone number and the alphanumeric word associated with each word. The telephone automatically dials the telephone number in response to an input spoken word matching the stored spoken word. In addition, the telephone number and alphanumeric text for the matched spoken word are displayed.
Proximity sensors are widely used in telephones e.g. for activating various functions.
U.S. Pat. No. 5,224,151 discloses a proximity sensor for use in a handset speakerphone that includes an infrared range detection unit built into the handset for controlling switching between a handset mode and a speakerphone mode.
U.S. Pat. No. 5,337,353 discloses a capacitive proximity sensor that includes a guard electrode and a sensor electrode separated by an insulating layer. For example for controlling switching between a handset mode and a speakerphone mode.
U.S. Pat. No. 5,712,911 discloses a telephone system for activating a speakerphone in response to an incoming call based upon the presence or absence of a subscriber within a predetermined proximity zone. The system includes a proximity unit and a control unit for automatically activating the speakerphone to establish communication with the caller when the subscriber is within the predetermined proximity zone.
U.S. Pat. No. 3,109,893 discloses a proximity operated telephone in which proximity switches are used for turning the telephone on when a subscriber passes his hand near the sensor to establish communication with the caller, and turning off the telephone when the subscriber again passes his hand near the sensor to terminate the communication with the caller.
European Patent Application No. 541439 discloses an auditory communication device using a proximity detector to activate a microphone when a speaker is present within a predetermined proximity zone. Thereby effects of ambient noise are reduced.
Thus, speech recognition means for activation of voice controlled functions and proximity sensors are well-known technical features.
Previously, speech recognition techniques were considered to be very sensitive to ambient noise and only to accept a very precise pronouncement of the commands. However, with recent developments within this field, these problems have been solved. But in fact, this has turned out to create a new problem, in that such recent speech recognition means react on spoken words, in the proximity of the speech recognition means, not intended to be a command to the speech recognition means. So in this way it is not possible to have the speech recognition means activated at all times without generating unintended results. It should be noted that one of the intentions of speech recognition is to avoid the use of buttons, keypads, and similar means which require a more or less complicated manual operation. Typically, such speech recognition means are embodied as programs executed by a central processing unit (CPU). Thus, when the speech recognition means constantly work on processing samples representing any ambient sound, much battery power is consumed by the CPU, analog-to-digital converters, etc.
An object of the present invention is to avoid unintended activation of voice controlled functions in an electrical device. A further object of the invention is to conserve battery operating power.
This is achieved when an electronic device according to the invention includes a proximity sensor for providing a control signal indicative of whether an object is in the proximity of the device and control means for controlling the voice controlled operation of the device in response to the control signal.
Consequently, the speech recognition means is activated only when it is intended to activate a function by means of a spoken command; this is determined in response to whether an object is in the proximity of the electronic device. That is, e.g., by moving a hand near the device. In this way, it is possible to avoid buttons entirely if desired, since the device can be activated by a movement and commanded by voice. This is very important for, e.g., drivers of a car, since then they only have to move, e.g., their hand close to the device instead of locating and holding down a specific button to activate the speech recognition means. Consequently, a much simpler and less distracting procedure for activating the speech recognition means is obtained.
Moreover, the invention relates to a method of detecting proximity.